The outline of the present road network was traced in the early 1930s, soon after the discovery of oil. The four main islands and all the towns and villages are linked by excellent roads. There were 3,164 km (1,996 mi) of roadways in 2002, of which 2,433 km (1,512 mi) were paved. A four-lane, 2.8-km (1.7-mi) causeway and bridge connect Manama with Al-Muharraq, and another bridge joins Sitra to the main island. A four-lane highway atop a 24-km (15-mi) causeway, linking Bahrain with the Sa'udi Arabian mainland via Umm an-Nasan, was completed in December 1986 and financed by Sa'udi Arabia. In 2000, there were 172,684 passenger vehicles and 41,820 commercial vehicles.
Bahrain's port of Mina Sulman can accommodate 16 oceangoing vessels drawing up to 11 m (36 ft). In 2001, Bahrain had a merchant fleet of eight ships of 1,000 GRT or over, totaling 270,784 GRT. Also in 2001, there were four airports, three of which had paved runways. The international airport near Al-Muharraq can handle large jet aircraft and serves more than two dozen international airlines. In 1997, the airport was in the midst of a major expansion. Gulf Air, headquartered in Bahrain and owned equally by the governments of Bahrain, Oman, Qatar, and the United Arab Emirates (UAE), flies to other Gulf countries, India, and Europe. In 2001, 1,250,100 passengers were carried on scheduled domestic and international flights.